Introducing World Missions: A Biblical, Historical, and Practical Survey is an excellent text for prospective missionaries and others interested in missions work. Though definitely a textbook and not a casual or quick read, this book's strength is its breadth. "Written as a textbook, its focus is on providing students in introductory missions courses with a broad overview as well as occasional deeper explorations" (from the preface). This would be a great resource for anyone teaching a class on missions or mentoring those considering missionary service.
The book is divided into five parts: (1) Encountering Missions in the Scriptures; (2) Encountering Missions in History; (3) Encountering Missions as a Candidate; (4) Encountering Missions as a Sent One and as a Sender; and (5) Missions Encountering the Contemporary World.